2003-01-23 19:12:25

by Chris Friesen

Subject: is it possible to bridge virtual devices (ie. a GRE tunnel)?

I want to set up two physically separate LANs with the same network
address and logically bridge them using some kind of tunnel over an IP
network.

I was hoping to somehow combine bridging with GRE tunnels in the kernel
to accomplish this, but I haven't been able to find out for sure if the
current kernel bridging code can handle a tunnel device as one of the
bridge elements.

Can anyone give the definitive answer for this?

Thanks,

Chris

--
Chris Friesen | MailStop: 043/33/F10
Nortel Networks | work: (613) 765-0557
3500 Carling Avenue | fax: (613) 765-2986
Nepean, ON K2H 8E9 Canada | email: [email protected]

2003-01-23 19:32:49

by Kevin P. Fleming

Subject: Re: is it possible to bridge virtual devices (ie. a GRE tunnel)?

Chris Friesen wrote:
>
> I want to set up two physically separate LANs with the same network
> address and logically bridge them using some kind of tunnel over an IP
> network.
>
> I was hoping to somehow combine bridging with GRE tunnels in the kernel
> to accomplish this, but I haven't been able to find out for sure if the
> current kernel bridging code can handle a tunnel device as one of the
> bridge elements.
>
> Can anyone give the definitive answer for this?
>
> Thanks,
>
> Chris
>

I don't believe you'd be able to use GRE tunnels, as they are not an "Ethernet"
type of tunnel.

However, I run a network with three physical locations, bridged over TAP-type
tunnels using VTUN (vtun.sourceforge.net). These are Ethernet-type tunnel
devices, so the bridge code just sees them as if it was any other Ethernet
network interface.

In addition, I use ebtables to control what traffic gets bridged across the
tunnels, so extraneous broadcast/multicast traffic stays where it is supposed to.